EP0318649A2 - Positive-working radiation-sensitive composistion and radiation-sensitive recording material produced therefrom for high-energy radiation - Google Patents

Abstract

A positive-working radiation-sensitive mixture is proposed which contains a compound which forms an acid under the action of high-energy radiation and a compound which is cleavable by acid and which is characterized in that the compound which forms an acid is aromatic contains bound chlorine or bromine and has a pK _a value of less than 12 or is a derivative of a compound with such a pK _a value.

The claimed mixture, in particular the recording material produced therefrom, has a higher sensitivity and an improved resolution and, moreover, shows no image fog after development.

Description

The invention relates to a positive-working radiation-sensitive mixture comprising a compound which forms an acid under the action of high-energy radiation and a compound which can be cleaved by acid.

In classic UV lithography, the resolution limit is determined by the wavelength of the radiation used. The constant reduction in dimensions in chip manufacture therefore requires new lithography techniques in the submicron range, with electron or X-rays being used because of their extremely short wavelength. It has been shown that resist materials which are suitable as electron beam resist can also be used as X-ray resist and vice versa.

Known resist materials for this application are acrylates and methacrylates (GM Taylor, Solid State Technology, 124 (1984)). These materials showed that sensitivity and structure resolution are usually opposing properties. If higher sensitivities are to be achieved, halogens are usually built into the resist. Fluorine and chlorine are usually present in positive working resists, and negative working resists against bromine and iodine rather than chlorine (T. Yamaoka et al., Phot. Sci. Eng. 23 , 196 (1979)).

In general, negative-working resists show a higher sensitivity than positive-working ones, but on the other hand, as explained above, they cannot have a high resolution in the submicron range. On the other hand, positive working resists based on methacrylate achieve a high resolution, but with the exception of resists based on polymethacrylonitrile they are not stable against the plasma etching processes used for semiconductor structuring. However, the methacrylates are not sufficiently sensitive.

The polymers with the highest known radiation sensitivity for electron or X-rays so far are polyalkene sulfones, in particular polybutene-1 sulfone. The disadvantage of this class of compounds is their less good resistance to plasma etching processes; They are therefore suitable for mask production, but not for semiconductor production with a mask made from this material. It has therefore been proposed to combine polyalkene sulfones with the known plasma etch resistant novolak resins (MJ Bowden et al., J. Electrochem. Soc. 128 , 1304 (1981); US-A-4,289,845). However, there was a strong incompatibility between the two polymers, which impaired the dissolution. Attempts to improve the compatibility by adding further components also had to be purchased with a loss of sensitivity (US Pat. No. 4,398,001).

Photocatalytic systems for use with electron and X-rays are described in DE-A-27 18 254 and DE-A-29 28 636. In these positive-working systems, chlorine-containing compounds, in particular of the substituted triazine type, are used as compounds which form an acid under the action of actinic radiation. When structuring these materials with electron or X-rays, however, it was found that the flanks of the resist structures after development have been negatively undermined (flank angle of 60 ° after being recorded with a scanning electron microscope (SEM)) and, as a result, structures below approx. 2 µm can no longer be resolved or imaged, or some of them are very frayed.

In DE-A-29 28 636, as in DE-A-26 10 842, a chlorine-containing compound is used inter alia. 2,3,4,5-Tetrachloroaniline called. In addition, DE-A-26 10 842 also discloses compounds which contain aliphatically bound bromine and one which carries bromine bound aromatically: 2,2 ', 4,4', 6,6'-hexabromodiphenylamine. However, it was found that a sufficiently high resolution cannot be achieved with the aromatic chlorine compound; with the compound mentioned, which contains aromatically bound bromine, on the other hand, undesirable image fog occurred.

The object was therefore to provide a positive-working radiation-sensitive mixture which is suitable for use as an electron or X-ray resist net, has a higher sensitivity and improved resolution, shows no image fog after development with an aqueous alkaline developer and has sufficient resistance to plasma etching.

The object is achieved by providing a positive-working radiation-sensitive mixture comprising a compound which forms an acid under the action of high-energy radiation and a compound which is cleavable by acid, characterized in that the compound which forms an acid is aromatically bound Contains chlorine or bromine and has a pK _a value of less than 12 or is a derivative of a compound with such a pK _a value.

It was completely surprising that compounds or starters which contain aromatically bound chlorine or bromine and have a pK _a value of less than 12, or their derivatives, have these advantageous properties, after the in the prior art (DE-A- 26 10 842) disclosed, aromatically bound halogen, in particular bromine-containing compounds, had proven to be unsuitable.

Of the acid-forming starters which contain aromatically bound chlorine or bromine, preference is given to those which have a pK _a value in the range from 6 to 10 or derivatives of these compounds.

The pK _a value of chemical compounds can be determined using conventional methods, but it is also a theoretical calculation using the "CAMEO" program and the like. possible.

In addition, in contrast to the known starters, the compounds used as starters show a low absorption in the spectral range above about 300 nm and thus enable work even under conventional laboratory lighting. Compared to the combination of brominated poly-p-vinylphenol with starter compounds mentioned in EP-A-0 111 274, which absorb essentially in the near UV range above 300 nm, besides these advantages there are also simplified formulations and fewer problems Compatibility and finally by mixing with novolaks as binders a targeted control of the development speed and thus also the sensitivity to radiation.

Suitable acid-forming starters are those which have at least one H atom which can be split off as a proton in the pK _a range mentioned. These include in particular compounds with carboxyl groups, phenolic OH groups, SH groups or correspondingly activated acid amide groups. However, these acidic groups are not required to be in free form. They can also be protected by suitable protective groups which can be split off under the conditions of processing, for example acetal, ester and certain ether groups, as are contained in the acid-cleavable compounds listed below. be protected. Under certain conditions, those compounds are also suitable as starters in which the acid groups mentioned are irreversibly substituted. If such compounds are to be used in aqueous developable mixtures, however, it is necessary that these mixtures contain substantial proportions of alkali-soluble binders.

mit mindestens einem aromatisch gebundenen Chlor- oder Bromatom, worin
R      Carboxyl, OR′ oder SR′,
R₁ und R₂      gleich oder verschieden sind und Wasserstoff, Chlor, Brom, Alkyl, ggf. substituiert durch Aryl-, Alkoxy-, Aryloxy-, Hydroxygruppen oder Fluoratome; Aryl, ggf. substituiert durch Alkoxy-, Aryloxy-, Hydroxygruppen oder Halogen­atome,
R′       Wasserstoff, Alkyl, ggf. substituiert durch Aryl-, Alkoxy-, Aryloxy-, Hydroxygruppen oder Fluoratome; Aryl, ggf. substituiert durch Alkoxy-, Aryloxy-, Hydroxygruppen oder Halogen­ atome; Acyl, Alkylsulfonyl, Arylsulfonyl, Alkoxy­carbonyl, Triorganosilyl, Triorganostannyl oder eine Alkylen-, Arylen-, Bisacyl-, Sulfonyl-, Alkylendisulfonyl-, Arylendisulfonyl-, Diorgano­silyl- oder Diorganostannylgruppe ist, deren zweite Valenz an das O-Atom einer weiteren Ein­heit der Formel I gebunden ist, wobei die Alkylen- und Arylengruppen entsprechend substi­tuiert sein können wie die Alkyl-und Arylreste,
und n      0 bis 3 bedeutet, wobei für n = 0:
A      Wasserstoff, Chlor, Brom, Alkyl, ggf. substi­tuiert durch Alkoxy-, Aryloxy-, Hydroxy-, Arylreste oder Fluoratome; Aryl, ggf. substi­tuiert durch Alkoxy-, Aryloxy-, Hydroxy-, Car­boxylreste oder Halogenatome,

für n = 1:
A      eine Einfachbindung, -O-, -S-, -SO₂-, -NH-, -NR₃-, Alkylen, Perfluoralkylen,

für n = 2:
A      -

R₃- oder -

- und

für n = 3:
A      -

- bedeutet,

sowie

Carboxyl, substituiertes Carbonyl, insbesondere Alkyl- oder Arylcarbonyl, Carboxyalkyl sowie sub­stituiertes Sulfonylimidocarbonyl und R₃      Alkyl, insbesondere (C₁-C₃)Alkyl, oder Aryl, ins­besondere Phenyl,
bedeutet.Acid-forming starters of the general formula I are particularly preferred

with at least one aromatically bound chlorine or bromine atom, wherein
R carboxyl, OR ′ or SR ′,
R₁ and R₂ are the same or different and are hydrogen, chlorine, bromine, alkyl, optionally substituted by aryl, alkoxy, aryloxy, hydroxy groups or fluorine atoms; Aryl, optionally substituted by alkoxy, aryloxy, hydroxyl groups or halogen atoms,
R ′ is hydrogen, alkyl, optionally substituted by aryl, alkoxy, aryloxy, hydroxyl groups or fluorine atoms; Aryl, optionally substituted by alkoxy, aryloxy, hydroxy groups or halogen atoms; Acyl, alkylsulfonyl, arylsulfonyl, alkoxycarbonyl, triorganosilyl, triorganostannyl or an alkylene, arylene, bisacyl, sulfonyl, alkylenedisulfonyl, arylenedisulfonyl, diorganosilyl or diorganostannyl group, the second atom of which is another unit on the formula I is bonded, where the alkylene and arylene groups can be substituted as the alkyl and aryl radicals,
and n denotes 0 to 3, where for n = 0:
A is hydrogen, chlorine, bromine, alkyl, optionally substituted by alkoxy, aryloxy, hydroxyl, aryl radicals or fluorine atoms; Aryl, optionally substituted by alkoxy, aryloxy, hydroxyl, carboxyl radicals or halogen atoms,

for n = 1:
A is a single bond, -O-, -S-, -SO₂-, -NH-, -NR₃-, alkylene, perfluoroalkylene,

for n = 2:
A -

R₃- or -

- and

for n = 3:
A -

- means

such as

Carboxyl, substituted carbonyl, especially alkyl or arylcarbonyl, carboxyalkyl and substituted sulfonylimidocarbonyl and R₃ alkyl, especially (C₁-C₃) alkyl, or aryl, especially phenyl,
means.

It is very particularly preferred if
R₁ and R₂ are the same and in particular are bromine, where they are each in the ortho position to R, and
R is a free hydroxy group or a hydroxy group protected by an acid-cleavable group.

Propylen oder Perfluorpropylen, wobei die beiden zuletzt genannten Substituenten vorzugsweise jeweils am gleichen C-Atom durch

substituiert sind,
oder
A      (für n=1 und B gleich Alkylcarbonyl, insbeson­dere Methylcarbonyl, Carboxyalkyl, insbesondere Carboxymethyl, substituiertes Sulfonylimidocar­bonyl, insbesondere p-Toluolsulfonylimidocarbo­nyl) -O-, -NH- oder -NR₃- oder
A      (für n=0) Hydroxyl, Carboxyl oder Alkyl, wel­ches an jedem zweiten C-Atom durch Phenyl, ggf. ein- oder mehrfach Brom enthaltend, substitu­iert ist,
bedeutet.It is also particularly preferred if
A (for n = 1 and B the same

Propylene or perfluoropropylene, the two last-mentioned substituents preferably each having the same carbon atom

are substituted,
or
A (for n = 1 and B is alkylcarbonyl, especially methylcarbonyl, carboxyalkyl, especially carboxymethyl, substituted sulfonylimidocarbonyl, especially p-toluenesulfonylimidocarbonyl) -O-, -NH- or -NR₃- or
A (for n = 0) hydroxyl, carboxyl or alkyl which is substituted on every second carbon atom by phenyl, optionally containing one or more bromines,
means.

Also particularly preferred are phenolic resins in which the unsubstituted o- or p-positions have been partially or completely chlorinated and / or brominated relative to the hydroxyl function.

Novolak types which are obtained by condensation of p-bromo-o, o'-bis-methylolphenol and optionally bromine-substituted m-cresol or compounds in which some of the phenolic hydroxyl groups are protected by cleavable groups are particularly preferred.

Compounds in which
for n = 0 and A equally substituted carbonyl:
R hydroxyl and
R₁ and R₂ each stand in the ortho position to R bromine, or
for n = 0 and A is optionally substituted alkyl:
R hydroxyl and
R₁ and R₂ each represent in the ortho position to R hydrogen or bromine.

The content of acid-forming initiators in the radiation-sensitive mixture according to the invention is generally 2 to 50% by weight, preferably 4 to 25% by weight, in each case based on the total weight of the layer.

If the starter is in polymeric form, in particular as part of the binder, the upper limit is the contents which are stated under the corresponding polymeric binders. The respective content of the starter or of the molecular groups responsible for the start in the polymer can be calculated from the mixing ratios of the monomeric starting components.

• a) solche mit mindestens einer Orthocarbonsäureester- ­und bzw. oder Carbonsäureamidacetalgruppierung, wobei die Verbindungen auch polymeren Charakter haben und die genannten Gruppierungen als verknüpfende Elemente in der Hauptkette oder als seitenständige Substituen­ten auftreten können,
• b) Oligomer- oder Polymerverbindungen mit wiederkehren­den Acetal- und/oder Ketalgruppierungen in der Haupt­kette,
• c) Verbindungen mit mindestens einer Enolether-, oder N-Acyliminocarbonatgruppierung,
• d) cyclische Acetale oder Ketale von ß-Ketoestern oder -amiden,
• e) Verbindungen mit Silylethergruppierungen,
• f) Verbindungen mit Silyl-enolethergruppierungen,
• g) Monoacetale bzw. Monoketale, deren Aldehyd- bzw. Ke­tonkomponente eine Löslichkeit im Entwickler zwischen 0,1 und 100 g/l aufweisen,
• h) Ether auf Basis tertiärer Alkohole und
• i) Carbonsäureester und Carbonate tertiärer, allylischer oder benzylischer Alkohole

The following classes of compounds have proven particularly useful as acid-cleavable material in the radiation-sensitive mixture according to the invention:

• a) those with at least one orthocarboxylic acid ester and / or carboxamide amide acetal group, the compounds also being polymeric in nature and the groupings mentioned can occur as linking elements in the main chain or as pendant substituents,
• b) oligomer or polymer compounds with recurring acetal and / or ketal groups in the main chain,
• c) compounds with at least one enol ether or N-acyliminocarbonate group,
• d) cyclic acetals or ketals of β-keto esters or amides,
• e) compounds with silyl ether groups,
• f) compounds with silyl enol ether groups,
• g) monoacetals or monoketals, the aldehyde or ketone component of which have a solubility in the developer of between 0.1 and 100 g / l,
• h) ethers based on tertiary alcohols and
• i) carboxylic acid esters and carbonates of tertiary, allylic or benzylic alcohols

Acid-cleavable compounds of type a) as components of radiation-sensitive mixtures are described in detail in EP-A-0 022 571 and DE-A-26 10 842; Mixtures containing compounds of type b) are shown in DE-C-23 06 248 and DE-C-27 18 254; Compounds of type c) are described in EP-A-0 006 626 and 0 006 627; Compounds of type d) are presented in EP-A 0 202 196 and compounds which are assigned to type e) in DE-A-3 544 165 and DE-A-3 601 264; Compounds of type f) can be found in the simultaneously filed patent application P 37 30 783.5, while compounds of type g) are dealt with in the likewise simultaneously filed patent applications P 37 30 785.1 and P 37 30 787.8. Connections of the type h) are, for. B. in US-A-4 603 101, compounds of type i) z. See, for example, U.S. 4,491,628 and JM Fréchet et al., J. Imaging Sci. 30: 59-64 (1986).

Mixtures of the acid-cleavable materials mentioned can also be used. However, preference is given to an acid-cleavable material which can be assigned to one of the types mentioned above. Of the materials, those of the types a), b), g) and i) are particularly preferred. The polymeric acetals deserve special mention under type b); of the acid-cleavable materials of type g), in particular those whose aldehyde or ketone component has a boiling point of greater than 150 ° C., preferably greater than 200 ° C.

The content of acid-cleavable material in the radiation-sensitive mixture according to the invention should be 1 to 50% by weight, preferably 5 to 25% by weight, in each case based on the total weight of the layer.

The radiation-sensitive mixture according to the invention also contains a water-insoluble, but at least swellable binder that is soluble in organic solvent and aqueous alkali. These primarily include phenolic resins of the novolak type. Phenol-formaldehyde resins, cresol-formaldehyde resins, their mixed condensates and their mixtures are mentioned.

In addition, vinyl polymers such as polyvinylacetals, polymethacrylates, polyacrylates, polyvinyl ethers, polyvinylpyrrolidones and styrene polymers, each modified by comonomers, if appropriate, themselves or in a mixture with others, can also be used.

Particular mention should be made of: polymers of styrene with units of alkenylsulfonylaminocarbonyloxy- or cycloalkenylsulfonylaminocarbonyloxy- (EP-A-0 184 804), polymers of acrylic, methacrylic, maleic, itaconic acid etc. with pendant, crosslinking -CH₂OR- Groups (EP-A-0 184 044), polymers from vinyl monomers with alkenylphenol units (EP-A-0 153 682), polyvinylphenols as novolak substitutes (DE-C-23 22 230), polymeric binders with pendant phenolic hydroxyl groups (EP-A -0 212 439 and 0 212 440), styrene-maleic anhydride copolymers (DE-A-31 30 987), polymers of unsaturated (thio) phosphinic iso (thio) cyanates with an active hydrogen-containing polymer (DE-A-36 15 612 and 36 15 613), polymers with vinyl acetate, vinyl alcohol and vinyl acetal units (EP-A-0 216 083) and polyvinylacetals with units from hydroxyaldehydes (DE-A-36 44 162).

The amount of binder is generally 1 to 90, in particular 5 to 90% by weight, preferably 50 to 90% by weight, based on the total weight of the radiation-sensitive mixture.

The binders mentioned, insoluble in water but soluble in alkali, can optionally be dispensed with if polymeric starters are used. Brominated polystyrenes or polyvinylphenols are particularly suitable for this. As a result, the content of the polymeric starter can also exceed the range described for the starter. In particular, salaries of greater than 50% by weight and up to 100% by weight minus the content of the compound which can be split by acid.

In addition, it is also possible to prepare the binder by condensation from a chlorine- or bromine-containing aromatic starter claimed according to the invention with a starting monomer which is known for the preparation of conventional binders. The prerequisite is that the acid-forming material containing chlorine or bromine has groups capable of condensation or polymerization.

On the part of the monomeric components of conventional binders, phenols and cresols, in particular m-cresol, are preferred for this condensation. The condensation is preferably carried out with approximately equimolar amounts.

In addition to this "condensation" of the chlorine- or bromine-containing starter with monomeric components of known binders to form a polymeric starter which also acts as a binder, simple mixing is also possible, but in this case of a polymeric starter and conventional binders. In particular, bromine-containing styrene derivatives are mixed with novolak resins, preferably in approximately equimolar proportions.

Dyes, pigments, plasticizers, wetting agents and leveling agents, but also polyglycols, Cellulose ethers, for example ethyl cellulose, can be added to improve special requirements such as flexibility, adhesion and gloss.

The radiation-sensitive mixture according to the invention is preferably used in solvents such as ethylene glycol, glycol ethers such as glycol monomethyl ether, glycol dimethyl ether, glycol monoethyl ether or propylene glycol monoalkyl ethers, in particular propylene glycol methyl ether; aliphatic esters such as ethyl acetate, hydroxyethyl acetate, alkoxyethyl acetate, n-butyl acetate, propylene glycol monoalkyl ether acetate, in particular propylene glycol methyl ether acetate or amyl acetate; Ethers such as dioxane, ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone and cyclohexanone; Dimethylformamide, dimethylacetamide, hexamethylphosphoric acid amide, N-methyl-pyrrolidone, butyrolactone, tetrahydrofuran, and dissolved in mixtures thereof. Glycol ethers, aliphatic esters and ketones are particularly preferred.

The solutions formed with the components of the radiation-sensitive mixture generally have a solids content of 5 to 60% by weight, preferably up to 50% by weight.

According to the invention, a radiation-sensitive recording material is also claimed, consisting essentially of a substrate and the radiation-sensitive mixture applied thereon.

Suitable substrates are all materials from which capacitors, semiconductors, multilayer printed circuits or integrated circuits can be made or manufactured. In particular, surfaces made of thermally oxidized and / or aluminum-coated silicon material may be mentioned, which may also be doped, including all other substrates customary in semiconductor technology, such as silicon nitride, gallium arsenide, indium phosphide. Also suitable are the substrates known from the production of liquid crystal displays, such as glass, indium tin oxide; also metal plates and foils, for example made of aluminum, copper, zinc; Bimetal and tri-metal foils, but also electrically non-conductive foils that are vapor-coated with metals, possibly with SiO₂ materials coated with aluminum and paper. These substrates can be subjected to a temperature pretreatment, surface roughened, etched or to improve desired properties, e.g. B. the increase in hydrophilicity, treated with chemicals.

In a particular embodiment, the radiation-sensitive mixture can contain an adhesion promoter for better adhesion in the resist or between the resist and the substrate. In the case of silicon or silicon dioxide substrates, there are adhesion promoters of the aminosilane type, such as 3-aminopropyl-triethoxysilane or hexamethyl-disilazane in question.

Examples of carriers used to make photome Mechanical recording layers such as printing forms for letterpress printing, planographic printing, screen printing, gravure printing and relief printing are aluminum plates, possibly anodized, granular and / or silicated aluminum plates, zinc plates, steel plates, which may have been chromed, and plastic films or paper.

The recording material according to the invention is irradiated imagewise with high-energy radiation sources; electron or X-ray radiation is preferred.

The layer thickness varies depending on its area of application. It is between 0.1 and 100 µm, in particular between 1 and 10 µm.

The invention further relates to a method for producing a radiation-sensitive recording material. The radiation-sensitive mixture can be applied to the substrate by spraying, flow coating, rolling, spin coating and dip coating. The solvent is then removed by evaporation, so that the radiation-sensitive layer remains on the surface of the substrate. If necessary, the removal of the solvent can be promoted by heating the layer to temperatures of up to 150 ° C. However, the mixture can also first be applied in the above-mentioned manner to an intermediate carrier, from which it is applied to the final carrier material under pressure and elevated temperature is transmitted. Basically, all materials that are also identified as carrier materials can be used. The layer is then irradiated imagewise. High-energy radiation such as X-ray or electron radiation is particularly preferred. High-energy synchrotron radiation with dose values of 20 to 200 mJ / cm² or radiation from an electron beam recorder is particularly preferred. An image pattern is then exposed in the radiation-sensitive layer by development by treating the layer with a developer solution which dissolves or removes the irradiated areas of the material.

Solutions of alkaline reagents such as e.g. Silicates, metasilicates, hydroxides, hydrogen or dihydrogen phosphates, carbonates or hydrogen carbonates, in particular of alkali or ammonium ions, but also ammonia and organic ammonium bases and the like are used. The content of these substances in the developer solution is generally 0.1 to 15% by weight, preferably 0.5 to 5% by weight, based on the weight of the developer solution.

In order to increase the resistance to mechanical and chemical influences, in particular to etching media, the developed layers can be heated for some time, for example 5 to 40 minutes, to an elevated temperature, for example above 100 ° C., this effect being further increased by exposure to UV Radiation can be supported.

The following examples are intended to illustrate the preparation of the compounds contained in the radiation-sensitive mixture according to the invention, some of which contain new aromatic chlorine or bromine:

Production Example 1: Hexafluorotetrabromo-bisphenol A

0.2 mol of hexafluoro-bisphenol A (2,2-bis- (4-hydroxyphenyl) -1,1,1,3,3,3-hexafluoropropane) was dissolved in 100 ml of glacial acetic acid while stirring. A solution of 0.8 mol of bromine in 100 ml of glacial acetic acid was added dropwise at a temperature of 30 to 60 ° C. and the reaction mixture was then heated under reflux until the HBr elimination was complete. The hot reaction mixture was stirred into 2 l of warm water, cooled to room temperature, and the crystals formed were suction filtered through a suction filter. The melting point of the product purified by sublimation was determined to be 255 ° C.

Production example 2: 1,1,1-tris (3,5-dibromo-4-hydroxyphenyl) ethane

102 g of tris (4-hydroxyphenyl) ethane were suspended in a mixture of 500 ml of glacial acetic acid and 250 ml of water. At 10 ° C., 334 g of bromine were then added dropwise to the stirred suspension. After the bromine had reacted, 750 ml of water were added and the crystals which had precipitated were filtered off with suction through a suction filter. They were washed with water, recrystallized from toluene and then dried. The product had a melting point of 276-278 ° C. The NMR spectrum (CDCl₃) showed the following signals: CH₃: 2.05 ppm (s, 3H); OH: 5.89 ppm (s, 3H); Phenyl: 7.1 (s, 6H).

Production example 3: N- (2,4,6-Tribromophenyl) -N ′ - (p-toluenesulfonyl) urea

50 mmol of 2,4,6-tribromaniline was dissolved in 20 ml of tetrahydrofuran. A solution of 50 mmol of toluenesulfonyl isocyanate in 20 ml of tetrahydrofuran was added dropwise at room temperature, and the stirred reaction mixture was then kept at 40 ° C. for 3 hours. The precipitated crystals were sucked off through a suction filter. After recrystallization from toluene, the product had a melting point of 230 ° C.

Production Example 4: Oligomer from tetrabromo-bisphenol A and 1,4-divinyloxy-butane

56.6 g of tetrabromobisphenol A are dissolved in 50 ml of tetrahydrofuran (THF) and 14.8 g of divinyloxybutane are added. After 3 hours of stirring at room temperature, the volatile constituents are distilled off on a rotary evaporator under a water jet vacuum. The remaining colorless solid has a melting point of 79 ° C and shows 1 H-NMR signals at 7.25 ppm (s, aroma), 5.60 ppm (q, acetal) and 1.57 ppm (methyl).

Production example 5: Tetrabromo-bisphenol-A-bis (1-ethoxy-ethyl ether)

56.6 g of tetrabromo-bisphenol A are dissolved in 50 ml of tetrahydrofuran, then 15 g of vinyl ethyl ether and 0.2 g of Amberlyst are added. After 3 hours under reflux, 5 g Potassium carbonate is added at room temperature, the mixture is stirred for an hour, then filtered and concentrated. The remaining highly viscous brown oil shows NMR signals at 7.27 ppm (s, aroma), 5.60 ppm (q, acetal) and 1.60 ppm (methyl).

Production example 6: Tetrabromo-bisphenol-A-bis (trimethylsilyl ether)

56.6 g of tetrabromo-bisphenol A are dissolved in 50 ml of THF. After adding 40 g of pyridine, 22.5 g of trimethylchlorosilane are added dropwise at room temperature. After heating under reflux for one hour, the mixture is worked up by shaking with diethyl ether and water. After concentration of the ether fraction, crystals are obtained which have a melting point of 141 ° C. recrystallized from isopropanol. NMR: 7.26 ppm (s, arom.), 1.60 ppm (s, Me₃Si).

Production Example 7: Tetrabromo-bisphenol-A-bis-tetrahydropyranyl ether

56.6 g of tetrabromo-bisphenol A are dissolved in 50 ml of THF. After adding 17.5 g of dihydropyran and 0.25 g of Amberlyst, the mixture is heated under reflux for 3 h, neutralized after cooling by adding 5 g of potassium carbonate, stirred for an hour and, after filtration, evaporated to dryness: oil. NMR: 7.27 ppm (aroma), 6.0 ppm (t, acetal), 1.57 ppm (methyl).

Production Example 8: Tetrabromo-bisphenol-A-bis (tert.butyl carbonate)

13.6 g of tetrabromo-bisphenol A are dissolved in 50 ml of THF. After slowly adding 2.65 g of sodium hydride (50%), 10.9 g of di-t-butyl carbonate are added dropwise. After four hours of stirring at 60 ° C is poured onto ice water, shaken three times with 150 ml of ethyl acetate, the organic phase dried and filtered. After recrystallization from isopropanol, the crystals obtained after concentration show a melting point of 172 ° C. NMR: 7.22 ppm (aroma), 1.57 ppm (s, 6H), 1.52 ppm (s, 18H).

Production Example 9: Tetrabromo-bisphenol-A diacetate

27.2 g of tetrabromo-bisphenol A are dissolved in 176.6 ml of pyridine. For this purpose, 7.8 g of acetyl chloride are slowly added dropwise with cooling and the reaction mixture thus obtained is kept at room temperature overnight. After filtration is poured onto ice water, with conc. HCl acidified. The precipitated ester is filtered off with suction, taken up in methylene chloride and washed with sodium bicarbonate solution and water, dried and concentrated. The product is recrystallized from acetonitrile, m.p .: 169 ° C, NMR: 7.42 ppm, 2.40 ppm, 1.68 ppm.

Production Example 10: Tetrabromo bisphenol A dibenzoate

Preparation analogous to preparation example 9, but using benzoyl chloride instead of acetyl chloride. White crystals (from acetonitrile): F 219 ° C, NMR 1.75 ppm (6H, methyl), 14 H aroma.

Production Example 11: Tetrabromo-bisphenol-A-dibenzenesulfonate

The procedure is as in Preparation Example 9, but using benzenesulfonyl chloride instead of acetyl chloride. Crystals (from acetonitrile), F: 208 ° C, NMR: 1.65 (6H, methyl), aroma: 14 H.

Production Example 12: 1,1,1-tris- (4-hydroxy-3,5-dibromophenyl) ethane-tris- (1-ethoxyethyl ether)

The procedure is as in Preparation Example 5, with the difference that the compound from Preparation Example 2 and the vinyl ethyl ether are used in a three-fold molar excess instead of bisphenol A. NMR: 1.17 ppm (t, methyl), 1.57 ppm (d, methyl), 5.57 ppm (q, acetal), 7.10 ppm (s, aroma).

Production example 13: Tetrabromo bisphenol A dimethyl ether

54.4 g of tetrabromo-bisphenol A are dissolved in 200 ml of 5% NaOH. 30.3 g of dimethyl sulfate are added dropwise at room temperature, the mixture is stirred at room temperature for one hour, then heated to 40 ° C. and 50 ml of conc. Ammonia solution added. The product is extracted with methylene chloride, the organic phase is washed, dried and concentrated. NMR: 7.3 ppm (s, aroma. 4H), 3.88 ppm (s, CH₃O, 6H), 1.6 ppm (s, CH₃, 6H).

The following application examples, in which Gt means parts by weight, are intended to explain the invention in more detail.

example 1

A coating solution was made from
17 pbw of a cresol-formaldehyde novolak with a softening range of 105-120 ° C,
5 pbw of a polymeric acetal from benzaldehyde and hexane-1,6-diol analogous to preparation example 19 in DE-C 27 18 254 and
4 pbw of tetrabromo-bisphenol A in
74 pbw of propylene glycol methyl ether acetate.

The solution was spun onto a silicon wafer treated with an adhesion promoter (hexamethyl-disilazane) at 3,000 rpm. After drying at 85 ° C. for 30 minutes in a forced air oven, a layer thickness of 1 μm was obtained. Irradiated with synchrotron radiation (BESSY, Berlin, air gap 2 mm) at a dose of 44 mJ / cm² through a gold-on-silicon mask. The experimental setup can be found in A. Heuberger, "X-Ray Lithography", Microelectronic Engineering 3 , 535-556 (1985). After exposure, the resist layer was left at room temperature for 30 minutes. Developed with an alkaline developer of the following composition:
5.3 pbw of sodium metasilicate x 9 H₂O,
3.4 pbw of trisodium phosphate x 12 H₂O,
0.3 pbw of sodium dihydrogen phosphate and
91 gt demineralized water.

After a development period of 30 s, an error-free image with all details of the mask was obtained. The re Sist flanks were not negatively undermined and showed angles of almost 90 ° (in a picture from a scanning electron microscope (SEM)).

Example 2

A coating solution and a resist were prepared in accordance with Example 1; Instead of the starter specified there, however, hexafluorotetrabromo-bisphenol A (preparation example 1) was added in the same amount. The results with regard to resolution and angle of the resist flanks to the substrate after development with the developer from Example 1 were comparable to those from Example 1.

Example 3

A coating solution according to Example 1 was prepared. Instead of tetrabromo-bisphenol A, however, bis (3,5-dibromo-4-hydroxyphenyl) sulfone in cyclohexanone was used as the starter. After exposure of the resist, it was developed in the developer according to Example 1, the development time being reduced to 20 s; the results with regard to resolution and resist edges again corresponded to those that could also be developed in Example 1.

Example 4

Instead of the tetrabromobisphenol A used in Example 1, tetrachlorobisphenol A was used in a coating solution which otherwise corresponded entirely to that of Example 1. The solution was with one a silicon wafer provided with an adhesion promoter according to Example 1 (3,000 rpm). After drying for 1 minute at 110 ° C. on a hot plate, a layer thickness of 1 μm could be obtained. Irradiation was carried out with synchrotron radiation (dose: 22 mJ / cm²). Development was carried out after a waiting time of only two minutes with a developer obtained by diluting the developer of Example 1 with deionized water in a ratio of 1: 1 within 25 seconds. Under these conditions it was possible to achieve structure reproductions as in example 1.

Example 5 (comparative example)

A coating solution was prepared as in Example 1, except that 4-iodophenol was used instead of the tetrabromo-bisphenol A. Coating was carried out in accordance with Example 1. In this example, however, no image could be obtained even with synchrotron radiation at a dose of 250 mJ / cm 2 after the development according to Example 1.

Example 6

This example corresponded to Example 1, except that 1,1,1-tris (3,5-dibromo-4-hydroxyphenyl) ethane was used instead of the starter specified there. The image was irradiated with synchrotron radiation at a dose of 30 mJ / cm². After development according to Example 1, results were obtained in resolution and angle of the resist flanks to the carrier, which corresponded to those from Example 1. In addition, the resist according to this example had an improved heat level.

Example 7

Instead of tetrabromo-bisphenol A, 2,4,6-tribromoacetanilide was used as the starter in this example. All other parameters corresponded to those of Example 1, with the exception that a dose of 170 mJ / cm² was irradiated imagewise with synchrotron radiation. The results were comparable to those from Example 1.

Example 8

In this example, N- (2,4,6-tribromophenyl) -N '- (p-toluenesulfonyl) urea was used as starter in accordance with the instructions from Example 1. Irradiation was carried out with synchrotron radiation at a dose of 160 mJ / cm². All other parameters corresponded to those of Example 1. The results with regard to resolution and resist edges were also comparable to those of Example 1.

Example 9

Instead of the starter used in Example 1, 2,4,6-tribromophenoxyacetic acid was used in this example. Irradiation was carried out with synchrotron radiation at a dose of 160 mJ / cm². Development was carried out with the developer from Example 1, but in this case the mixture was diluted with demineralized water in a ratio of 1: 1. All other parameters were identical to those from example 1. An error-free, high-resolution image according to Example 1 could be achieved.

Example 10

This example was the same as Example 9, except that 3,5-dibromo-4-hydroxy-benzoic acid was used as the starter. The results corresponded to those from Example 8.

Example 11

A coating solution containing was prepared
11 pbw of a brominated poly- (p-hydroxy) styrene with a bromine content of 50% by weight (commercial product of the Maruzen),
11 pbw of the phenolic resin from Example 1,
5 pbw of an acetal from benzaldehyde and phenoxyethanol according to the manufacturing instructions in
73 pbw of propylene glycol methyl ether acetate.

It was coated, irradiated and developed in accordance with Example 1. With synchrotron radiation at a dose of 35 mJ / cm 2, the resolving power and behavior of the resist flanks were identical to those from Example 1.

Manufacture of benzaldehyde diphenoxyethylacetal

0.5 g of p-toluenesulfonic acid was added to a mixture of 1 mol of benzaldehyde, 2 mol of phenoxyethanol and 1.1 mol of trimethyl orthoformate with cooling. The mixture was stirred at room temperature for 2 h. A water jet vacuum was then applied to the mixing apparatus sets and stirred for 2 h at 20 ° C, 40 ° C and 60 ° C. Finally, the reaction mixture was passed through a thin-film evaporator at 80 ° C. and a pressure of 0.1 torr. If necessary, a further distillation can be carried out in a thin-film evaporator at a correspondingly elevated temperature.

The resulting acetal was stirred with Na₂CO₃, K₂CO₃ or basic aluminum oxide, whereby the acid catalyst was neutralized. The solid components were separated off and the filtrate was concentrated in vacuo. The acetal in its present form could be used in a recording material. It had a melting point of 22-24 ° C; no CO signal was detectable in the IR spectrum; the NMR spectrum (CDCl₃) showed an acetal signal at δ = 5.76 ppm.

Example 12

A coating solution containing was prepared
22 pbw of a bromine-containing novolak, produced from a mixture of 2,6-dimethylol-4-bromophenol and m-cresol (molar ratio 1: 1, acidic condensation),
5 pbw of the acetal from piperonal and phenoxyethanol in
73 pbw of propylene glycol methyl ether acetate.

Analogously to Example 1, a silicon wafer was coated with the coating solution and dried, then imagewise irradiated with synchrotron radiation at a dose of 81 mJ / cm 2 and developed.

The results were comparable to those from Example 1.

Production of piperonal-bis-phenoxyethylacetal

In addition to the acid and solvent from the preparation example in Example 11, 1 mol of piperonal and 2 mol of phenoxyethanol were introduced. According to the statements in Example 11, an acetal obtained as an oil could be isolated. It showed in the NMR spectrum (CDCl₃) the characteristic signal for acetals at δ = 5.66 ppm.

Example 13

A coating solution containing was prepared
11 pbw of a cresol-formaldehyde novolak with a softening range of 105-120 ° C,
11 pbw of a brominated poly (p-hydroxy) styrene with a bromine content of 50% by weight in accordance with Preparation Examples 1 to 3 and
5 pbw of an acetal from cyclohexanone and phenoxyethanol, which had been prepared according to the preparation instructions from Examples 11 and 12, in
73 pbw of propylene glycol methyl ether acetate.

It was coated, irradiated and developed in accordance with Example 1. With synchrotron radiation at a dose of 41 mJ / cm², results analogous to Example 1 could be achieved.

Example 14

A coating solution was prepared in accordance with Example 13, with the difference that α, p-bis-trimethylsilyloxystyrene according to the preparation example given below was used as the acid-cleavable material. The results were analogous to those of Example 12.

Production of α, p-bis-trimethylsilyloxystyrene

0.72 mol of trimethylchlorosilane and 1 mol of triethylamine were placed in 100 ml of dimethylformamide. 0.35 mol of p-hydroxyacetophenone was added dropwise with stirring at room temperature and then heated to 110 ° C. for 4 hours with stirring. After the reaction mixture had cooled, 100 ml of hexane were added and washed with water. After the extraction, the organic phase was subjected to fractional distillation. This gave 19 g of the desired bisether (boiling point: 125 ° C / 4 torr). The NMR spectrum showed on the basis of enolic protons at δ = 4.19 and 4.65 ppm that the carbonyl groups had completely changed into enol ether groups.

Example 15

A coating solution containing was prepared
16 pbw of poly (4-tert-butoxycarbonyl) styrene and
4 pbw of tetrabromo-bisphenol A in
80 pbw of propylene glycol methyl ether acetate.

Coating and irradiation were carried out in accordance with Example 1.

After the irradiation, the mixture was dried in a forced air oven at 120 ° C. for 30 minutes. The sample shown was then processed further in accordance with Example 1. The results in terms of resolving power and resist flank configuration corresponded to those from Example 1.

Example 16

A coating solution containing was prepared
7 pbw of a cresol-formaldehyde novolak with a softening range of 105-120 ° C,
7 pbw of brominated poly (p-hydroxy) styrene with a bromine content of 50% by weight in accordance with Preparation Examples 1 to 3 and
3 pbw of an acetal of 4-ethylbenzaldehyde and phenoxyethanol according to the preparation example given below in
83 pbw of propylene glycol methyl ether acetate.

Coating was carried out in accordance with Example 1. After drying the resist in a forced air oven according to Example 1, a dry layer thickness of 0.3 μm was obtained.

The image was irradiated with an electron beam recorder at an acceleration voltage of 50 kV with a radiation dose of 1 µC / cm².

The subsequent development with the developer according to Example 1 was able to provide an error-free image with a resolution of 0.3 μm over a development period of 30 s.

Preparation of 4-ethylbenzaldehyde bis-phenoxyethyl acetal

1 mol of 4-ethylbenzaldehyde and 2 mol of phenoxyethanol were reacted in accordance with the preparation instructions in Example 11. An acetal with a melting point of 48 ° C. could be isolated. The NMR spectrum (CDCl₃) showed a signal for an acetal at δ = 5.74 ppm.

Examples 17-26

Coating solutions with the starter compounds of Preparation Examples 4 to 13 were prepared with the following composition:
17 gt of a cresol-formaldehyde novolak with a softening range of 105 - 120 ° C
5 pbw of an acetal from benzaldehyde and phenoxyethanol, prepared as described in Example 11,
4 Gt of each starter in
74 pbw of propylene glycol methyl ether acetate.

The production of the resist film and the irradiation with X-rays were carried out analogously to Example 1. After development under the conditions given in Table 1, structural reproductions were achieved which corresponded to the 0.3 μm structures contained on the mask.

The resist flanks were not negatively undermined and had a flank angle of almost 90 ° when SEM was assessed. Tab. 1 Starter from manuf. Ex. Dose BESSY 805 MeV Developer ^x ) Development time (s) 4th 180 mJ / cm² 1: 1 20th 5 80 mJ / cm² 1: 0.33 30th 6 25 mJ / cm² 1: 0 60 7 180 mJ / cm² 1: 0 50 8th 90 mJ / cm² 1: 0.5 60 9 75 mJ / cm² ^xx ) 20 (surfactant additive) 10th 75 mJ / cm² ^xx ) 10 " 11 75 mJ / cm² 1: 0 20 " 12 75 mJ / cm² 1: 0 165 13 90 mJ / cm² 1: 0 200 ^x ) Developer from Example 1, diluted in the specified ratio with deionized water ^xx ) Developer according to Example 1, but only with 76.7 pbw of demineralized water

Example 27:

The procedure was as in Example 17, but with the difference that the compound from Preparation Example 5 as the starter and the silyl ether as the solution inhibitor acc. Example 14 was used. After imagewise irradiation with 90 mJ / cm² and development with developer diluted 1: 0.5 according to Example 1, a very good resist pattern was obtained within 60 s.

Example 28:

Analogously, when using the starter from preparation example 10 and tris-phenoxyethyl orthoformate after irradiation with 90 mJ / cm 2 and development for 150 s, a very good resist pattern is obtained in the developer of example 1.

Claims (9)

1. A positive-working radiation-sensitive mixture containing a compound which forms an acid under the action of high-energy radiation, and a compound which can be split by acid, characterized in that the compound which forms an acid contains aromatically bound chlorine or bromine and has a pK _a value of less than 12 or is a derivative of a compound with such a pK _a value. 2. Radiation-sensitive mixture according to claim 1, characterized in that the acid-forming compound has a pK _a value of 6 to 10 or is a derivative of such a compound. 3. Radiation sensitive mixture according to claims 1 or 2, characterized in that the acid-forming compound is a compound of general formula I.

with at least one aromatically bound chlorine or bromine atom, wherein
R carboxyl, OR ′ or SR ′,
R₁ and R₂ are the same or different and are hydrogen, chlorine, bromine, alkyl, optionally substituted by aryl, alkoxy, aryloxy, hydroxy groups or fluorine atoms; Aryl, optionally substituted by alkoxy, aryloxy, hydroxyl groups or halogen atoms,
R ′ is hydrogen, alkyl, optionally substituted by aryl, alkoxy, aryloxy, hydroxyl groups or fluorine atoms; Aryl, optionally substituted by alkoxy, aryloxy, hydroxy groups or halogen atoms; Acyl, alkylsulfonyl, arylsulfonyl, alkoxycarbonyl, triorganosilyl, triorganostannyl or an alkylene, arylene, bisacyl, sulfonyl, alkylenedisulfonyl, arylenedisulfonyl, diorganosilyl or diorganostannyl group, the second atom of which is another unit on the formula I is bonded, where the alkylene and arylene groups can be substituted as the alkyl and aryl radicals,
and n denotes 0 to 3, where for n = 0:
A is hydrogen, chlorine, bromine, alkyl, optionally substituted by alkoxy, aryloxy, hydroxyl, aryl radicals or fluorine atoms; Aryl, optionally substituted by alkoxy, aryloxy, hydroxyl, carboxyl radicals or halogen atoms,

for n = 1:
A is a single bond, -O-, -S-, -SO₂-, -NH-, -NR₃-, alkylene, perfluoroalkylene,

for n = 2:
A -

R₃- or -

- and

for n = 3:
A -

- means
such as

Carboxyl, substituted carbonyl, especially alkyl or arylcarbonyl, carboxyalkyl and substituted sulfonylimidocarbonyl and R₃ alkyl, especially (C₁-C₃) alkyl, or aryl, especially phenyl,
means. 4. radiation-sensitive mixture according to claims 1 to 3, characterized in that the acid-forming compound is monomeric and the mixture contains a water-insoluble, but soluble in aqueous alkali binder. 5. Radiation sensitive mixture according to claims 1 to 3, characterized in that the acid-forming compound is polymer. 6. Radiation-sensitive mixture according to claim 5, characterized in that the acid-forming compound is a hydroxystyrene polymer or copolymer or a phenolic resin. 7. Radiation-sensitive mixture according to claims 5 or 6, characterized in that the mixture additionally contains a polymeric binder which is insoluble in water but soluble in aqueous alkali. 8. A positive-working radiation-sensitive recording material for high-energy radiation, consisting essentially of a support and a radiation-sensitive layer, characterized in that a radiation-sensitive mixture according to claims 1 to 7 is used. 9. A method for producing a positive-working radiation-sensitive recording material for high-energy radiation, characterized in that a radiation-sensitive mixture according to claims 1 to 7 is applied to a carrier which may be loaded with an adhesion promoter, the material dried, then with high-energy radiation, in particular X-ray - Or electron radiation, irradiated imagewise and finally the image is exposed by developing with an aqueous alkaline developer.